In recent years, along with the popularization of so-called hi-definition televisions, wide-screen televisions, and others, horizontally-long displays have been becoming common as television displays. Moreover, thinner systems are desired as television sets as a whole.
A speaker unit (hereinafter referred to as a speaker) used in a flat-screen television is required to have reduced width and thickness because of thinner design of a television and a so-called slim-type display which has thinner housing around the display. At the same time, audio with higher quality is also required along with increased quality of the display.
The following describes a conventional speaker 10 having a track-shaped long structure used in a flat-screen television with reference to FIGS. 15A to 15C.
FIG. 15A shows a top view of the conventional speaker 10 having the track-shaped long structure, FIG. 15B shows a sectional view seen from A-A′ in FIG. 15A, and FIG. 15C shows a sectional view seen from B-B′ in FIG. 15A.
In FIGS. 15A to 15C, the conventional speaker 10 having the track-shaped long structure includes a diaphragm 1, an edge 2, a voice coil bobbin 3, a voice coil 4, a plate 5, a magnet 6, a yoke 7, and a flame 8.
The outer periphery of the diaphragm 1 is adhered to the inner periphery of the edge 2. The shape of the diaphragm 1 is as follows: the planar shape viewed from the vibrating direction has a long side and a short side, the sectional shape in the short direction is hollow circular, and the both ends in the long direction is ¼ spherical.
The outer periphery of the edge 2 is fixed to the frame 8.
The voice coil bobbin 3 is adhered to the outer periphery of the diaphragm 1 and applies power on the diaphragm 1.
The voice coil 4 is held by the voice coil bobbin 3 in such a manner that the voice coil 4 is positioned in a magnetic gap G of a magnetic circuit.
The plate 5, the magnet 6, and the yoke 7 constitute an internal magnet type magnetic circuit. The internal magnet type magnetic circuit generates magnetic flux in the magnetic gap G formed between internal walls of the plate 5 and the yoke 7. As for the configuration of the magnetic circuit, the plate 5 is fixed on the top surface of the magnet 6, and the magnet 6 is fixed on the inner bottom surface of the yoke 7. Moreover, the plate 5, the magnet 6, and the yoke 7 are positioned such that the respective long directions match the long direction of the diaphragm 1, and the central axes approximately match.
The frame 8 is fixed at the bottom side of the end of the edge 2. Moreover, the frame 8 is also fixed on the bottom surface of the above magnetic circuit.
The following describes operations of the conventional speaker 10 having the track-shaped long structure as described above.
When a current is supplied to the voice coil 4, the supplied current and a magnetic field generated in the magnetic gap G generate driving force in the voice coil 4. The generated driving force is transmitted to the diaphragm 1 through the voice coil bobbin 3. The generated driving force causes the diaphragm 1, the voice coil bobbin 3, and the voice coil 4 to perform the same vibratory movement. Then, the vibration of the diaphragm 1 radiates sound to space.